Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/024—Multiple impregnation or coating
  • B01J37/0244—Coatings comprising several layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/78—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with alkali- or alkaline earth metals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/72—Copper
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C17/00—Preparation of halogenated hydrocarbons
  • C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
  • C07C17/15—Preparation of halogenated hydrocarbons by replacement by halogens with oxygen as auxiliary reagent, e.g. oxychlorination
  • C07C17/152—Preparation of halogenated hydrocarbons by replacement by halogens with oxygen as auxiliary reagent, e.g. oxychlorination of hydrocarbons
  • C07C17/156—Preparation of halogenated hydrocarbons by replacement by halogens with oxygen as auxiliary reagent, e.g. oxychlorination of hydrocarbons of unsaturated hydrocarbons

Definitions

• This invention relates to an industrial catalyst, its preparation, and its use, especially for the production of EDC by the oxychlorination of ethylene in a fluidizable or fixed bed reactor.
• the oxychlorination of ethylene to 1 , 2-dichloroethane (EDC) is known to be catalysed by catalysts containing, inter alia, copper, suitably in the form of its chloride, often in admixture with alkali metal salts, and carried on an alumina support.
• catalysts containing, inter alia, copper, suitably in the form of its chloride, often in admixture with alkali metal salts, and carried on an alumina support.
• Such catalysts have been described, as well as the related preparation methods, in several patents.
• the first patents claimed a simple catalyst prepared by impregnating a suitable support, often ⁇ -alumina, with a solution containing copper chloride.
• a real development of such catalyst was achieved by adding a further salt, chosen from among the alkali, alkaline-earth or rare-earth metals.
• binary, ternary and sometimes quaternary compositions are described in many patents, as well as different preparation methods.
• a typical example of a binary composition is described in EP 041330 (PPG) and is a catalyst prepared with copper and potassium chlorides .
• the claims refer to a real active phase constituted by KCuCl 3 .
• the method of preparation is based on a co-precipitation of CuCl 2 and KC1 on various supports, the preferred one being attapulgite clay.
• Copper content in the catalyst ranges from 4 to 12% by weight preferably between 7 and 9%.
• the molar ratio Cu:K is 1:1.
• Such a catalyst is said to be suitable for fluid bed applications.
• European Patent EP 119933 (MONTEPOLIMERI) describes a binary composition based on copper and magnesium, codeposited on the support as chlorides.
• the preferred support is ⁇ -Al 2 0 3 , preferably with a relatively high surface area and proper pore volume.
• the amount of copper in the catalyst lies in the range 1-10% by weight, while the magnesium content goes from 0 to 1 mole per mole of copper.
• the preparation method includes the use of HCl during the dry impregnation procedure.
• European Patent EP 176432 (AUSIMONT) describes a fluidizable catalyst. Copper and magnesium are the metals used and the crucial item in the preparation method is said to be the radial distribution of the active phase inside the support particles. In fact, a catalyst having less copper on the surface of the particles is claimed, with relevant reduction of sticking phenomena. Copper and magnesium content in the catalyst falls between 1 and 10% by weight, preferably between 2 and 6% for copper.
• EP 0278922 (ENICHEM SYNTHESIS) is described a catalyst for fluid bed applications and the method for its preparation based on ⁇ -alumina, Cu and alkali or alkaline earth metals. Copper content ranges from 3 to 7% by weight while from 0.01 to 4% of the aforesaid additives is included.
• the examples describe a ⁇ -Al 2 0 3 -supported catalyst containing Cu and Ca; a catalyst containing also Mg; and a catalyst which includes Li instead of Mg. All the catalysts were prepared by one-shot impregnation, with an aqueous solution of the salts. The oxychlorination reactions are carried out using an air-based process, operating with an oxygen excess.
• US Patent No. 4,446,249, describes the use of a catalyst containing copper on ⁇ -alumina, wherein the support is modified prior to the deposit of copper by incorporating in it from 0.5 to 3.0% by weight, based on the weight of the support, of at least one metal selected from the group consisting of potassium, lithium, rubidium, caesium, alkaline earth metals, rare earth metals and combinations thereof, by admixing a water solution salt of metal (s) with the ⁇ -Al 2 0 3 , support, drying the mix and calcining it at 350 to 600°C for about 4 to 16 hours.
• US Patent No. 3,624,170 claims a ternary catalytic composition based on CuCl 2 , NaCl and MgCl 2 , the atomic ratio Cu:Na:Mg being 1:0.2-0.7:0.3-1.5.
• Such catalyst is claimed to avoid the deactivation caused by contaminaton due to FeCl 3 present inside the stainless steel reactors.
• EP-A-0255156 (SOLVAY) describes ternary catalytic compositions containing a mixture of copper chloride, magnesium chloride and an alkali metal chloride which is sodium chloride or lithium chloride, used in precise proportions, which enable a good yield to be achieved in a fluidized bed process for the oxychlorination of ethylene to 1, 2-dichloroethane, simultaneously reducing the corrosion of stainless steel reactors as a result, in particular, of a reduction in the sticking and clumping of the particles of catalyst.
• This document teaches that, for ternary compositions containing copper chloride, magnesium chloride and sodium chloride as an alkali metal chloride, a Na/Cu atomic ratio above 0.2:1 leads to problems of corrosion of the reactor.
• Patent US 4,849,393 describes catalysts containing, besides copper chloride and an alkali metal salt, a rare earth metal salt.
• the catalysts contain from about 2% to about 8% by weight of copper, from about 1% to about 10% by weight of a rare earth metal salt and from about 0.25% to about 2.3% by weight of an alkali metal salt. All the salts are co-deposited on a suitable support by means of the dry impregnation procedure, to give a catalyst which allows high ethylene efficiency and low stickiness.
• copper chloride, potassium chloride and one or more rare earth metal chlorides an excellent catalyst for fluid bed ethylene oxychlorination is obtained.
• composition of the catalyst claimed in EP A 0375202 in which is described a ternary catalytic composition based on copper chloride, magnesium chloride and potassium chloride. Copper content ranges from 3 to 9% by weight, while that of magnesium and potassium is from 0.2 to 3%.
• the preferred atomic ratios Cu:Mg:K are 1:0.2-0.9:0.2-09.
• US Patent No. 5,260,247 (SOLVAY) describes a quaternary catalytic composition based on CuCl 2 , MgCl 2 , LiCl and at least one other alkali metal chloride on an inert support (A1 2 0 3 ) . Also in this patent the support is impregnated with the metal salts in one shot.
• the examples refer to an air-based oxychlorination process, operating with an oxygen excess of 36% and a Cl/C ratio of 0.95.
• a catalyst which is suitable for catalysing the oxychlorination of ethylene to 1,2- dichloroethane, which comprises a ⁇ -alumina support coated with a first layer containing magnesium and, on the first layer, a second layer containing copper and, optionally, lithium.
• the invention also provides a process for preparing a catalyst suitable for catalysing the oxychlorination of: ethylene to 1, 2-dichloroethane, which comprises impregnating ⁇ -alumina with a solution containing a magnesium salt, drying the product, and impregnating the product with a solution containing a copper salt and, optionally, a lithium salt.
• the catalyst suitably contains, by weight, from 0.1 to 5%, preferably 0.1 to 2%, magnesium; from 2 to 10%, preferably 2 to 8%, copper; and from 0 to 5%, preferably 0 to 1%, lithium.
• a particularly preferred catalyst contains, by weight, 0.5 to 1.5% magnesium; 3 to 6% copper; and 0.1 to 0.3% lithium.
• the ⁇ -alumina used as the catalyst support preferably is one having a siurface area of from 50 to 220 nr/g, especially 80 to 180 m 2 /g, and an average particle size in the range 40 to 60 ⁇ .
• the ⁇ -alumina is dried, in order to remove water adsorbed inside its pores, and is then impregnated with a solution of a magnesium salt, suitably magnesium chloride.
• a magnesium salt suitably magnesium chloride.
• the product is dried, suitably overnight, and it is then impregnated with a solution of a copper salt, suitably copper chloride, either alone or, preferably, in combination with a lithium salt, again suitably as lithium chloride.
• the product of this second impregnation step is then dried.
• Three catalysts were prepared by impregnating ⁇ -alumina with 1) copper chloride, 2) copper chloride and magnesium chloride, and 3) magnesium chloride.
• the catalysts were treated with acetone, which is able to dissolve CuCl 2 and MgCl 2 , but not copper or magnesium aluminate, nor the copper hydroxo-complexes, such as paratacamite Cu 2 (OH) 3 Cl.
• the catalyst containing only copper had its metal content reduced from 4 to 3.52%, while the presence of magnesium enhanced the amount of free copper chloride, leaving only 2.92% copper on the catalyst.
• the activation may be carried out directly inside the fluid bed pilot reactor.
• the synergistic effect due to this preparation procedure provides a very efficient catalyst for ethylene oxychlorination, particularly for the oxygen-based process, which operates by recycling the vent gas and with low oxygen excess and low Cl/C ratios.
• This synergistic effect represents a substantial advantage over known methods.
• GEON which describes a two-steps preparation procedure where the additive (s) are added prior to copper deposition
• the method requires a calcination after the first impregnation, so that the support is modified through a reaction between the support and the alkali, alkaline-earth or rare earth metal salt(s).
• the support which is impregnated with the copper chloride solution has changed.
• no other salt is present in the solution used for the second dry impregnation.
• the present invention is not based on a bulk modification of the support and a following simple impregnation with copper chloride, but rather modifies chemically only the surface of the support by means of magnesium aluminate formation and at the same time enhances the dispersion of copper, deposited in the second step together with lithium, whose ionic dimension induces the formation of highly dispersed small crystals.
• the core of such plant is the reactor, which is a tube made of nickel, 3m length, with an internal diameter of 40 mm. Reagents flowrates are controlled by mass flow meters through a computer system which also keeps under control the whole pilot plant (pressure, temperature, etc) .
• the products (EDC + water) are collected in a drum after condensation in a water condenser.
• the vent gas from the first condenser undergoes a further cooling by means of a glycol condenser.
• the final vent gas is neutralized by a caustic washing, but such stream is analyzed by an on-line GC before neutralization. In fact the caustic washing removes the C0 2 present in that stream and this would not allow a correct mass balance.
• All the catalysts were prepared following the dry impregnation procedure, i.e. by adding to the support a volume of solution equal to the total pore volume available.
• the support used for preparing the catalyst was a ⁇ alumina having a surface area of about 180 m 2 /g, a pore volume of about 0.5 cc/g and a mean particle size of 45-50 ⁇ m.
• Such alumina was dried at 120 °C for 4 hours before the impregnation, in order to remove the water adsorbed inside the pores.
• Two kilograms of catalyst were prepared for each Example described below.
• the impregnation was carried out with solutions containing CuCl 2 and/or MgCl and/or LiCl in amounts which ensure the final compositions reported in Table 2.
• the equipment used for the dry impregnation procedure was a rotary vessel. After each impregnation, a drying step at 80 °C overnight was carried out. The activation was performed at 200 "C inside the pilot reactor under nitrogen flow. For all the samples the atomic ratios Cu:Mg:Li are 2:1:1.
• the catalysts were tested by using them in ethylene oxychlorination reactions carried out at the following operating conditions:
• the average productivity of the catalyst achieved at these operating conditions is around 648g EDC /h. kg cat , which means an enhancement of ca.21% with respect to Examples 1-6 and ca.9% in comparison with Examples 7-8.
• the oxychlorination catalysts of the present invention show substantial advantages over those previously proposed.
• the benefits reported in the Examples for pilot scale procedures represent very substantial savings when extrapolated to full-scale industrial production.

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• Chemical & Material Sciences (AREA)
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• Engineering & Computer Science (AREA)
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• Chemical Kinetics & Catalysis (AREA)
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• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

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• 1998
  • 1998-01-08 EP EP98300097A patent/EP0931587A1/en not_active Withdrawn
• 1999
  • 1999-01-06 AU AU17787/99A patent/AU1778799A/en not_active Abandoned
  • 1999-01-06 DE DE69901676T patent/DE69901676T3/de not_active Expired - Lifetime
  • 1999-01-06 SK SK1034-2000A patent/SK10342000A3/sk unknown
  • 1999-01-06 TR TR2000/01773T patent/TR200001773T2/xx unknown
  • 1999-01-06 CN CN99802018A patent/CN1287507A/zh active Pending
  • 1999-01-06 IL IL13629699A patent/IL136296A0/xx active IP Right Grant
  • 1999-01-06 WO PCT/IB1999/000065 patent/WO1999034918A1/en not_active Application Discontinuation
  • 1999-01-06 US US09/582,887 patent/US6777373B1/en not_active Expired - Lifetime
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  • 1999-01-06 KR KR1020007006392A patent/KR20010040296A/ko not_active Application Discontinuation
  • 1999-01-06 CA CA002317580A patent/CA2317580A1/en not_active Abandoned
  • 1999-01-06 HU HU0100374A patent/HUP0100374A3/hu unknown
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  • 1999-01-06 EP EP99900096A patent/EP1045731B2/en not_active Expired - Lifetime
  • 1999-01-06 JP JP2000527353A patent/JP4608094B2/ja not_active Expired - Lifetime
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  • 1999-01-07 ZA ZA9900102A patent/ZA99102B/xx unknown
  • 1999-06-01 UA UA2000084711A patent/UA63987C2/uk unknown
• 2000
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